Method for modifying a well to provide gas lift production

ABSTRACT

In the method, a perforating device equipped with perforation forming means is lowered through a conventional tubing string and locked with a collar recess at a predetermined subsurface location. On a second trip, a remotely operable actuating device is lowered into engagement with the perforating device and operated to actuate the perforating device which in turn forms perforations through the wall of the surrounding tubing string. On the return leg of the second trip, the perforating device is unlocked and removed from the tubing string along with the attached actuating device. On a third trip, a gas lift valve is lowered through the tubing and anchored with the same collar recess to provide regulated valving of fluids flowing through the perforations. The system includes a perforating device and a separate actuating device. The actuating device is lowered into engagement with the perforating device following locking of the perforating device with a subsurface collar recess. The actuating device is surface operated to ignite a charge carried in the perforating device which produces a cutting jet stream to form perforations in the surrounding tubing string. The perforating and actuating devices are locked together for removal as a unit. The system includes a gas lift valve provided with radially movable collar recess anchoring members and axially spaced, self expanding seal members for respectively anchoring the valve with the collar recess and providing a seal above and below the perforations whereby the valve regulates the flow of fluids through the perforations.

United States Patent 91 Garrett [451 Oct. 29, 1974 1541' METHOD FORMODIFYING A WELL TO PROVIDE GAS LlFT PRODUCTION [75] Inventor: Henry U.Garrett, Houston, Tex.

[73] Assignee: v Brown Oil Tools, Inc., Houston,

Tex.

[22] Filed: Nov. 16, 1973 [21] Appl. No.: 416,358

Related US. Application Data [62] Division of Ser. No. 209,128, Dec. 17,1971, Pat. No.

[52] US. Cl. 166/297, 166/315 [51] Int. Cl E21b 43/14, E2lb 43/11 [58]Field of Search 166/297, 315, 55.1

[56] References Cited UNlTED STATES PATENTS 3,496,953 2/1970 Garrettl66/55.l X 3,530,948 9/1970 Garrett 166/55.l X 3,642,070 2/1972 Tayloret al. 166/297 3,677,346 7/1972 Tamplen 166/315 Primary ExaminerDavid H.Brown Attorney, Agent, or FirmTorres & Berryhill 5 7] ABSTRACT In themethod, a perforating device equipped with perforation forming means islowered through a conventional tubing string and locked with a collarrecess at a predetermined subsurface location. On a second trip, aremotely operable actuating device is lowered into engagement with theperforating device and operated to actuate the perforating device whichin turn forms perforations through the wall of the surrounding tubingstring. On the return leg of the second trip, the perforating device isunlocked and removed from the tubing string along with the attachedactuating device. On a third trip, a gas lift valve is lowered throughthe tubing and anchored with the same collar recess to provide regulatedvalving of fluids flowing through the perforations.

The system includes a perforating device and a separate actuatingdevice. The actuating device is lowered into engagement with theperforating device following locking of the perforating device with asubsurface collar recess. The actuating device is surface operated toignite a charge carried in the perforating device which produces acutting jet stream to form perforations in the surrounding tubingstring. The perforating and actuating devices are locked together forremoval as a unit. The system includes a gas lift valve provided withradially movable collar recess anchoring members and axially spaced,self expanding seal members for respectively anchoring the valve withthe collar recess and providing a seal above and below the perforationswhereby the valve regulates the flow of fluids through the perforations.

2 Claims, 15 Drawing Figures PMENTED UN 29 1974 8MB! 10F 4 agea'aszPATENTED UB1 29 1974 P ii METHOD FOR MODIFYING A WELL TO'PROVIDE GASLIFT PRODUCTION BACKGROUND OF THE INVENTION This is a division ofapplication Ser. No. 209,128, filed Dec. 17, 1971 now US. Pat. No.3,789,923.

l. Field of the Invention The present invention relates to methods andmeans for equipping a well with gas lift apparatus for artificialproduction of the fluids contained within the well. More specifically,the present invention relates to methods and means for equipping aconventional production tubing string with gas lift valves.

2. Brief Descriptionof the Prior Art When the subsurface pressure withina petroleum bearing formation drops below the point required tonaturally elevate the petroleum effluents through the well'structure atan efficient rate, artificial lifting of the fluids is usually required.Such artificial production is normally effected by simple mechanicalpumping or by the use of gas lift techniques. In the latter method ofartificial production, pressurizedgas is injected'into the well from thewellhead and gaslift valves in the well structure are employed toregulate the flow of the gas into the conduit through which the wellfluids flow. Normally, the fluid containing conduit is the productiontubing string and gas is insertedinto the'annular area between theproduction string and'the surrounding casing where it is injected intothe tubing string by means of gas lift valves secured to the tubingstring.

ment'and retrieval of the gas lift valves'after the tubingstring is inplace.

When the future need for gas lifting of a newly completed well isanticipated before the production tubing is installed, special landingnipples may be included in the tubing string as the string is-insertedinto'the well. In this prior art technique, following decline in thenatural formation pressure, a perforating device is employed to formopenings through the landing nipple and specially designed gas liftvalves are then lowered through the tubing string and landed in thenipple.

The replacement of an entire string is undesirable because of theexpense and lost production time associated with removing the originaltubing stringand replacing it with a gas lift equipped string. While thesecond prior art method of pre-equipping the string with special landingnipples overcomes this-objection, many of the older wells are equippedonly with conventional tubing. If the future need for gas liftinganynewly completed well is questionable, the extra expense required forthe use of special pre-installed landing nipples may be prohibitive.Moreover, subsequent changes in formation conditions may require thepositioning of the gas lift valves at points other than those where thelanding nipples are located.

Prior art processes and equipment employed to convert a conventionaltubing string for gas lift operation may require as many as fiveseparate trips to install each gas lift valve. As used herein, the termtrip is employed to define a procedure in which a running tool or otherequipment is lowered through the well and thereafter returned to thewells surface. A single lowering and subsequent raising to the surfaceis considered to be a trip."

The perforating equipment employed in prior art systems is often subjectto dangerous prefiring since the perforating means and the actuating orfiring mechanisms are handled as a unit in a single trip. Moreover,conventional devices intended for use as gas lift valves in aconvertedconventionalt'ubing string normally require a mechanism for anchoringthe assembly in place and a second separate mechanism intended toprovide the valving function. Because of the need'for separatecomponents, the complexity of the system is increased and there is acorresponding decline in reliability.

SUMMARY OF THE INVENTION In the method of the present invention, onlythree trips are required to install a gas lift valve in a conventionalproduction tubing string. On the first trip, a perforating device islowered through the tubing string to the desired subsurface location andlocked with a collar recess formed between two connecting tubingsections. On the second trip, an actuating or firing device is loweredinto locking engagement with the perforating device. Surfacemanipulation of the actuating device ignites a shaped charge in theperforating device which in turn produces a cutting jet stream to form aperforation in the tubing string. On the return portion of thesecondtrip, the perforating device and actuating device are removed tothe surface as a unit'and on a third trip, a gas lift valve equippedwith self-expanding seals is lowered into the tubing string and lockedinto the collar recess to provide the desired valving of fluidsflowingthrough the perforations.

In the method of the present invention, only three trips are required toinstall each gas lift valve. Since the perforating device and theactivating means are moved' downwardly through the tubing string inseparate trips, there is no danger of prefiring. Additional safety isprovided by forming the perforations below the point where theperforating device is anchored with the tubing string. In addition,anchoring the perforating'device and the gas lift valve from the samecollar recess ensures precise placement of the valve assembly about theperforation.

The system of the present invention includes a perforating device whichis surface operated and may be anchored with any subsurface collarrecess in the tubing string. A running tool is employed to position andlock the perforating device in the tubing string. Premature release isprevented by safety members which hold the running tool with theperforating device until radially movable locking dogs have beenexpanded into a collar recess.

The perforating device is equipped with a charge which when ignitedproduces a cutting jet action which forms a perforation in the tubingstring. An impact responsive ignition or discharge control is carried bythe perforating device and when struck, ignites the cutting charge. Theignition control is protected from inadvertent impact and the requireddischarging impact may be provided only by a separate actuating orfiring device which is designed to engage the perforating device afterthe latter has been securely anchored at the desired subsurfacelocation. Surface manipulation of the actuating device provides thedesired discharge impact and locks the actuating device and perforatingdevice together for removal from the tubing string as a unit.

The gas lift valve of the present invention is designed to anchor withthe same collar recess previously holding the perforating device so thatthe valve is precisely positioned with respect to the perforations. Thevalve assembly is equipped with self-expanding seals which provide aleakproof flow passage between the perforation and the valve. Theanchoring means, seal and valve form a single assembly which ispositioned within and retrieved from the tubing string as a unit.

From the foregoing, it may be appreciated that the present inventionpermits a conventional tubing string to be equipped with gas lift valveswithout the need for removing the tubing string and without the use ofpreinstalled, specially designed landing nipples. Because of thecooperating design of the perforating device, activating device and gaslift means, only three trips are required to perforate the tubing stringand equip it with a gas lift valve. The equipment and method of thepresent invention permit separate handling of the perforating device andthe actuating mechanism required to effect operation of the perforatingdevice. The gas lift valve is self anchoring and scaling to eliminatethe need for separate components.

The foregoing as well as other features and advantages of the presentinvention will be more fully appreciated from the followingspecification, drawings and related claims.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a vertical quarter-sectionillustrating the perforating device of the present invention beinglowered through a tubing string to a subsurface collar recess;

FIG. 2 is a view similar to FIG. 1 illustrating the perforating devicebeing locked into engagement with a collar recess;

FIG. 3 is a vertical elevation in quarter section illustrating anactuating device landed within the perforating device;

FIG. 4 is a quarter sectional elevation illustrating the actuatingdevice of FIG. 3 locked into engagement with the perforating device;

FIG. 5 is a view similar to FIG. 4 illustrating the actuating devicedelivering an impact to the discharge control means in the perforatingdevice;

FIG. 6 is a view similar to FIG. 5 illustrating the perforating devicereleased from the tubing string prior to removal of the perforatingdevice and the actuating mechanism from the tubing string;

FIG. 7 is a view similar to FIG. 6 illustrating the perforating deviceand actuating mechanism being moved upwardly through the tubing string;

FIG. 8 is a vertical elevation, in quarter-section, illustrating the gaslift valve assembly of the present invention being lowered into thetubing string;

FIG. 9 is a view similar to FIG. 8 illustrating the valve assembly justbefore being anchored into the collar recess;

FIG. If) is a view similar to FIG. 9 illustrating the valve assemblylocked into engagement with the collar recess with the running toolreleased;

FIG. 11 is a vertical elevation in quarter-section illusthe tubingstring;

FIG. 12 is a horizontal section taken along the line I2I2 of FIG. 2;

FIG. 13 is a horizontal cross-section taken along the line l3-l3 of FIG.2;

FIG. 14 is a horizontal cross-section taken along the line 14-14 of FIG.3; and

FIG. 15 is a horizontal cross-section taken along the line 15-15 of FIG.8.

DESCRIPTION OF THE PREFERRED EMBODIMENT AND METHOD PERFORATING DEVICEFIG. I of the drawings illustrates the perforating device of the presentinvention, indicated generally at 10. The perforator I0 is illustratedbeing lowered through a conventional tubing string T by means of awireline running tool, indicated generally at R, suspended from awireline W. While the present invention is described as being employedwith wireline apparatus, it will be appreciated that other conventionalmethods or equipment may be employed to position, actuate and retrieveequipment of the present invention. In general, the perforating device10 is designed to be locked into a tubing collar recess C, released fromthe running tool R and subsequently engaged and actuated by a separateactuating mechanism to form a perforation in the tubing string T.

The perforating device 10 is equipped with one or more jet perforationforming means 11 designed to be ignited by a primer cord 12 to cutopenings through the tubing T. The primer cord is ignited by an impactresponsive discharge control 13. The control 13 is a replaceable powderfilled cartridge connected to a dynamite cap and is discharged by animpact delivered through an axially movable firing pin 14 mounted in apin housing 14a. A hammer 15 carried above the pin 14 is fixed againstmovement by a shear pin 15a until actuated by a separate device to bedescribed.

The outer housing of the perforator 10 is formed from threadedly engagedcooperating components which include a lower shoe section 16, anintermediate pin mounting section 17, a body section 18, a latch cagesection 19 and an upper retaining collar 20. The lower shoe section 16mounts and supports the control 13. The jet perforation forming means IIis threadedly mounted within the tubular wall of the shoe section 16 andan O-ring seal 22 is positioned between the means II and the shoe toform a leakproof connection between the two components.

As may best be seen by joint reference to FIGS. 1,2 and 13, the upperend of the perforating device I0 includes a plurality of dogs 25 whichare designed to be moved radially outwardly by axial movement of asetting sleeve 26. The dogs 25 include upper and lower tapered heads 25aand 25b respectively which cooperate with upper and lower taperedrecesses 26a and 26b, respectively to control anchoring and release ofthe perforating device within the tubing string T. It will beappreciated that relative movement between the dogs 25 and sleeve 26acts through the engaged tapered surfaces to tend to move the dogs outof the recesses. A shear pin 27 extends between the setting sleeve 26and an inner, loading sleeve 28. A short control sleeve 29 is carriedbetween the setting sleeve 26 and loading sleeve 28 and a plurality ofaxially developed, resilient collet fingers extend downwardly from ashoulder formed at the upper end of the control sleeve 29. While only asingle collet 30 is seen in H0. 1, it will be appreciated that aplurality of circumferentially spaced, axially extending collets similarto the collet 30 depend from the upper end of the sleeve 29. The lowerend of each of the collets is provided with an enlarged head 30. Whenthe components of the perforator 'are in the position illustrated inFIG. '1, the collet heads 30a are biased inwardly into an annular recess28a formed on sleeve 28. A recess 260 formed along the internal wall ofthe sleeve 26 is adapted to receive the collet heads 30a when thevarious perforator components have been moved relative to each otherinto the positions illustrated in FIG. 2. A shoulder 26d formed on theouter wall of the sleeve 26 is employed to prevent relative movementbtween the anchoring components in a manner to be hereinafter described.

' A coil spring 31 is positioned between the base of the sleeve 28 andthe top of a pin keeper sleeve 32a which in turn is slidably carriedover a safety lock sleeve 32. A rod 33 extends coaxially through thesleeve 32 and the compressed spring 31. The rod 33 is provided with aslot 33a which receives a shear pin 34'carried by the sleeve 32 and heldin place by the keeper sleeve 32a. Flanged locking dogs 35 extendthrough radial openings formed through the base of the sleeve 32 andproject into a recess 18a formed in the housing member 18. ln theposition illustrated in FIG. 1, a circumferential ridge 33b formed aboutthe rod 33 maintains the dogs 35 extended radially outwardly through theopenings formed in the sleeve 32 to prevent separation of the perforatorl0 and running tool R.

Referring jointly to FIGS. 1, 2 and 12, several holding dogs 36 aremounted for radial movement through the control sleeve 26 and whenextended, move into a recess a in the collar 20 during the procedureused to anchor the perforator to the tubing string. The loading sleeve28 is movable with respect to the rod 33 to permit preliminarypositioning of the dogs 35 and positioning of the collet heads 30a inthe recess 28a. The spring 31 remains compressed until the perforator isanchored.

ANCHORING THE PERFORATOR FIG. 1 illustrates the perforatingdevice l0 andrunning tool R as they appear when the assembly is being lowered throughthe tubing string. During the lowering procedure, the spring 31 pushesthe sleeves 28 and 32 apart. The base of sleeve 32 engages the base ofrecess 18:: in the housing section 18 and tends to move the attachedhousing section 19 away from the sleeve 26 which is pinned to the sleeve28. The opposing movement between section 19 and sleeve 26 urges thedogs outwardly so that the heads 25b are dragged against the internaltubing string wall as the perforator is lowered. When the heads 25aregister with a collar recess, additional outward radial movement of thedogs is permitted and the dogs move into the recess. The lower ends ofthe heads 25b are tapered so that the dogs are moved inwardly when theyengage the base of the collar recess so that the assembly may continueto move down through the tubing string with a ratchet-like action.

When the desired subsurface location has been reached, the running toolR is stopped and the perforator 10 is raised upwardly through the tubingstring T. As the dogs 25 encounter the first collar recess C in theupward movement, they are moved radially outwardly into the recess.Continued upward movement of the setting tool R is resisted byengagement of the dog heads 25b with the upper end of the collar recess.The tapered surfaces on the setting sleeve 26 and on the dogs 25 tend tourge the dogs further outwardly as greater lift force is exerted tothereby prevent upward movement of perforator 10. This additionallift'further compresses the spring 31 and engages the top of keepersleeve 32a with the base of loading sleeve 28. When sufficient lift isexerted by the running tool R, the pin 27 shears so that the perforatorcomponents move into the anchored position illustrated in FIG. 2 of thedrawings. Thus, once the pin 27 has been severed, the force of thecompressed spring 31 is suddenly released to move the sleeve 28 upwardlywith respect to the anchored perforator 10. This upward movement actsthrough the collets 30 to lift the control sleeve 29, dogs 36 andsetting sleeve 26 upwardly relative to the housing section 19 whichcauses the dogs 36 to move outwardly. The collet heads 30a spring intothe recess 26c to maintain the control sleeve 29 in an upper positionwhich in turn retains the dogs 36 at their outermost radial position inthe recess 20a.

In the anchored position illustrated in H0. 2, the upper and lower dogheads, 25a and 25b, respectively, have been moved out of the settingsleeve recesses 26a and 26b. In the anchored position, heads 25b extendradially into the collar recess to the extent required to preventmovement of the perforating device 10 axially above or below the recess.The engagement of dogs 36 with the base of the recess 26a prevents thecontrol sleeve 26 from being moved downwardly with respect to the dogs25 and the engagement between the base of the collar 20 and the shoulder26d on the control sleeve 26 prevents the control sleeve from movingupwardly with respect to the dogs 25. Continued upward movement of therod 33 severs the pin 34 permitting the rod to move into the positionillustrated in FIG. 2 which frees the dogs 35 and permits the runningtool to separate from the anchored perforating device.

The dogs 35 and ridge 33b cooperate to form a safety mechanism whichprevents separation of the perforating device 10 and setting tool Rbefore the dogs 25 have been moved into and locked in their radiallyouter position. Thus, until the dogs 25 have been expanded radiallyoutwardly into the position shown in FIG. 2, upward movement of thesleeve 32 and control rod 33 draws the dogs 35 into engagement with thetop of recess 18a preventing separation of the running tool R andperforator 10. Since the dogs 25 are not extended into the recess C, theupward movement draws both the running tool R and perforator l0upwardly.

THE ACTUATING MECHANlSM (FIGS. 3-7) Once the perforating device 10 hasbeen anchored to the collar recess C, the running tool R and attachedsetting assembly are removed from the tubing to complete the first tripof the method. On the first leg of the second trip, an actuatingmechanism indicated generally at A is lowered through the tubing stringT and into engagement with the anchored perforating device 10. Themechanism A includes a tubular running head which is suspended from thewireline W. A mandrel 41 extends centrally through the member 40 and isheld in axial position within the member 40 by a shear pin 42. A coilspring 43 is positioned over the mandrel 41 between the base of themember 40 and the upper end of a keeper sleeve 44a set over a lockingsleeve 44. A laterally extending shear pin 45, held in position by thesleeve 44a, extends through the sleeve 44 and through an axiallydeveloped slot 46 formed in the mandrel 41. The lower end of the mandrel41 is threadedly engaged to a shoe portion 47 and an annular ridge 48 isformed along the lower portion of the mandrel. Referring jointly toFIGS. 3 and 14, a plurality of locking dogs 49 are disposed between themandrel 41 and the surround ing sleeve 44 and are designed to be movedradially through a slot formed in the sleeve 44. The dogs 49 projectinto the recess 18a to lock the actuating and perforating mechanismstogether. The lower end of the sleeve 44 is equipped with an end member50 which surrounds the mandrel 41 and acts as a guide for axial movementof the mandrel.

OPERATION OF THE ACTUATlNG MECHANISM AND PERFORATOR As the actuatingmechanism A is being lowered through the tubing string T and before itengages the perforating device 10, the components of the mechanism arein the relative positions indicated in FIG. 4. When the lower end of theactuating mechanism A engages the upper end of the anchored perforatingdevice 10, the mechanism telescopes downwardly into the perforatingdevice until the dogs 49 engage the upper end of collar 26. At thispoint, further downward movement of the actuating mechanism is preventedbecause of the radial extension of the dogs 49. Weighting means Mcarried by the wireline W are permitted to rest on the firing mechanismto compress the spring 43 which in turn permits the mandrel 41 to belowered into the position illustrated in FlG. 3 thereby permitting thedogs 49 to retract by moving off the ridge 48. With the dogs 49retracted, the actuating device may be moved into the positionillustrated in FIG. 4 where the spring 43 moves the sleeve 44 downwardlyover the mandrel 41 which in turn moves the dogs 49 radially outwardlyinto locking engagement with the recess 18a. After the dogs 49 are movedinto the recess 18a, the actuating mechanism A and perforating device Pare securely locked together.

When the cutting charge 11 in the perforating device 10 is to be ignitedor discharged, a downward blow is imparted to the mandrel 41. This blowmay be effected by the use ofjars or any other suitable means. Theimpact force is transmitted through the running head 40, through theshear pin 42 and to the mandrel 41 which in turn strikes the hammer l5severing the pin a. The sharp movement of the hammer 15 followingseverance of the pin 15a discharges the control 13 which ignites thecutting jet charge 11 to form the desired perforation P. It will beappreciated that the perforation forming means described herein areexemplary and that any suitable means carried by the device 10 may beemployed for forming a perforation in the tubing T. In the preferredembodiment, the member 13 is a powder charged cartridge employed toignite a dynamite cap. The element 12 is a primer cord ignited by thedynamite cap and 11 is a shaped charge which produces a torch-likecutting jet to form an opening through the tubing.

After the perforation has been formed, a second, stronger downwardlydirected blow is imparted to the head 40 by the jarring mechanismconnected to the wireline W. The mandrel 41 engages the hammer 14 whichin turn engages the housing section 17 to prevent further downwardmovement of the mandrel so that the second blow severs the shear pin 42and permits the head 40 to be moved downwardly over the mandrel 41.Downward movement of the head 40 brings it into engagement with thecontrol sleeve 26 which in turn moves the sleeve 26 down and permits thedogs 36 to be moved radially inwardly. This permits setting sleeve 26 tobe moved downwardly with respect to the dogs 25. Once the sleeve 26 hasbeen shifted downwardly as illustrated in FIG. 6, the dogs 25 are freeto move radially into and out of the recesses 26a and 26b and the dogs49 remain atop the ridge 48 so that the actuating mechanism andperforating device remain locked together and may be removed from thetubing string as a unit as illustrated in FIG. 7.

VALVE ASSEMBLY Following formation of the perforation P and removal ofthe perforating and actuating devices, the valving assembly of thepresent invention indicated generally at 60 in FlGS. 8-10, is loweredinto the tubing string by a running tool indicated generally at R-l. Aswith the perforating device and actuating mechanism, the valvingassembly 60 may be moved downwardly through the tubing string byconventional wireline equipment. FIG. 8 illustrates the assembly as itappears during the first leg or lowering portion of the third trip. Theassembly 60 is equipped with a releasable anchoring means similar tothat employed to anchor the perforating device 10. The valve anchoringcomponents employed in the valving assembly 60 are identified byreference characters which are higher by than the correspondingcomponents employed in the perforating device. The anchoring assemblyincludes: a cage member 119; top collar 120 with an internal recess120a; anchoring dogs with upper and lower head portions 125a and 125b,respectively; a setting and release sleeve 126; a shear pin 127; loadingsleeve 128; control sleeve 129 equipped with collets 130; coil spring131; safety sleeve 132; a setting rod 133; shear pin 134; dogs 135 anddogs 136.

Anchoring of the valve assembly 60 proceeds in the manner describedpreviously with respect to anchoring of the perforating device 10. Asthe assembly 60 is lowered through the well bore, upper and lowernormally expanded seals and 171 are maintained retracted to preventformation of a seal with the surrounding tubing string. When the desiredsubsurface location has been reached, the wireline is pulled upwardly tomove the anchoring members into positions illustrated in FIG. 9 withsubsequent upward pulling bringing the dogs 125 into the collar recess Cand permitting the shear pin 127 to sever as illustrated in H0. 10. ltwill be appreciated that the movement of the various components duringthe anchoring action is similar to that previously described withrespect to similar components in the perforating device 10.

The seals 170 and 171 are mounted between axially movable end structureswhich may move toward each other to permit the seals to expand radiallyoutwardly into sealing engagement with the surrounding tubing string T.To this end, the upper seal 170 is mounted over a tubular seal supportmember 173 which is threadedly engaged at its upper end with the lowerend of housing section 119. An upper seal mount member 174 holds theupper end of the seal 170 in place and a lower seal mount member 175 ispositioned over the support member 173. The lower mount member 175 isthreadedly engaged to a coupling 176 which supports a tubular housingsection 178 and a valve mounting section 179. As illustrated in FIGS.8-10 and 15, a conventional gas lift valve V is threadedly mountedwithin a recess formed in the section 179.

The lower end of the valve mounting section 179 is threadedly engaged toa second tubular coupling member 180 which in turn is threadedly engagedto an upper seal mount member 181 holding the upperend of the seal 171in position. A tubular seal support member 182 extends centrally withinthe seal 171 and provides a support for a lower seal mount member 183.The upper end of the support 182 is threadedly engaged to a headedbushing 184 and its lower end is tapered to assist in guiding theassembly downwardly through the tubing string.

Resilient O-ring seals are provided between the various componentsmaking up the valve assembly to ensure a leakproof seal above and belowthe perforation P when the seals 170 and 171 are moved outwardly intosealing engagement with the tubing string T. During placement of theassembly 60 within the tubing string, the seals 170 and 171 are retainedin radially retractd position by a spacer bar 185 secured to the lowerend of the sleeve 132 and extending to the top of bushing 184. Thespacer bar maintains the end structures for each of the seals at theirgreatest axial separation. The normal resiliency of seal 170 tends todraw the tubular sleeve 176 upwardly along the supporting sleeve 173which in turn tends to permit the seal to expand radially outwardly. Acontinuous sliding seal between the support member 173 and surroundingcoupling sleeve 176 is provided by an annular O-ring seal 186.Similarly, the natural resiliency of seal 171 tends to draw the supportmember 182 upwardly through the surrounding sleeve a function of thepressure of the injection gas and/or the pressure of the fluids withinthe tubing string.

The seals 170 and 171 are similar and are selfexpanding once the spacerrod 185 is released and removed from the assembly 60. The seals arepreferably of the design illustrated and function to provide a leakproofseal against pressures developed either above or below the seal. Forthis purpose, the seals are equipped with an annular groove such as thegroove 170a in the seal 170. A plurality of radially directed openings1711b extend through the seal and open into a void annular 180 to permitthe seal 171 to expand radially outwardly. A continuous sliding seal ismaintained between the support member 182 and the surrounding coupling180 by an annular O-ring seal 187. When the running mechanism R-1 islatched into the valve assembly 60 in the manner illustrated in FIGS. 8and 9, the spacer bar 185 maintains the relatively slidable componentsat their extended position so that the seals 170 and 171 remainretracted radially to prevent formation of a seal between the assembly60 and the surrounding tubing string T. The headed bushing 184 engageseither an internal shoulder formed in the coupling 80 or the base ofmounting section 171 to limit axial travel of the support 182. Axialmovement of the support 173 is limited by engagement of a shoulder 173awith the top of section 178 and an internal shoulder in section 176.

OPERATION OF THE VALVE ASSEMBLY Once the dogs 125 in the assembly 60have been expanded into the recess as illustrated in FIG. 10, therunning assembly R-1 may be removed from the tubing. in the anchored,sealing position illustrated in FIG. 10, the valve assembly 60 providesa fluid-tight seal above and below the perforation P so that injectiongas in the area external to the tubing string T may enter the annulararea between the tubing string and the outer housing of assembly 60where it may be injected into the tubing string T by the valve V. Thevalve V carried by the assembly 60 is conventional and functions toregulate the flow of injection gas into the tubing string T as area 170dformed behind the seal. When the assembly is in the position illustratedin FIG. 10, the higher gas pressure entering the annular area betweenthe seals 170 and 171 is communicated through the openings 170a into theupper portion of the annular opening 170d behind the seal 170. Thispressure is higher than the pressure in the tubing string T and tends toexpand the upper portion of the seal 170 radially outwardly into tightsealing engagement with the surrounding tubing string wall. It will beappreciated that the seal 171 operates in the same manner with theexception that the gas pressure tends to extend the lower portion of theseal radially outwardly into sealing engagement with the surroundingtubing string.

VALVE RETRIEVING APPARATUS In FIG. 11, a retrieving apparatus indicatedgenerally at R-2 is illustrated locked into position with the valveassembly 60. The assembly R-2 includes a tubing control member 211extending over a central control rod 212. The upper end of the member211 is threadedly engaged to a sleeve 213 which extends upwardly throughthe center of a coil spring 214. The rod 212 is provided with an axiallyextending slot 215 and the member 211 supports a laterally extendingshear pin 216 which passes through the slot 215. The upper end of therod 212 is threadedly engaged to a retaining member 217 which issupended from a running tool (not illustrated). The external surface ofthe member 211 is equipped with upper and lower shoulders 211a and21112, respectively. The lower end of rod 212 is equipped with acircumferential ridge 2120 which is adapted to move under locking dogs218 projecting through openings formed in the lower portion of themember 211.

RETRIEVING THE VALVING ASSEMBLY When the valving assembly 60 is to beremoved from anchoring engagement with the tubing T, the retrievingapparatus R-2 is lowered through the tubing string and into engagementwith the assembly 60 so that the shoulder 211b engages the top of collet129. Continued lowering compresses the spring 214 and moves the collet129 downwardly through the surrounding sleeve 126 freeing the dogs 136.Subsequent lowering of the apparatus R-2 brings the shoulder 211a intoengagement with the top of sleeve 126 to move the sleeve downwardly.Once the dogs 136 are retracted, the spring 214 snaps the pin 216 to thebase of slot 215 so that the ridge 212a is moved below the dogs 218causing the dogs to project radially outwardly and engage the base ofthe sleeve 173 to prevent separation of the retrieving mechanism and thevalve assembly 60. With the sleeve 126 moved to its lower position, thedogs are free to retract radially into the position illustrated in FIG.11 which permits the entire assembly to be withdrawn from the tubingstring T.

Although not specifically illustrated, it will be appreciated that theretrieving mechanism R-2 may be equipped with a suitable spacer rod topush the bushing 184 downwardly thereby causing retraction of the seals170 and 171 to facilitate retraction of the assembly from the tubingstring. In the event the assembly 60 should become wedged in the tubingstring T, the running mechanism R-2 may be separated from the assembly69 by pulling upwardly sufficiently to sever the shear pin 216. With thepin 216 severed, the rod 212 and ridge 212a may be raised to the pointnecessary to permit retraction of dogs 218.

The foregoing disclosure-and description of the invention isillustrative and explanatory thereof, and various changes in the size,shape and materials as well as in the details of the illustratedconstruction may be made within the scope of the appended claims withoutdeparting from the spirit of the invention.

1 claim:

1. A method of providing gas lift valves in a conventional tubing stringcomprising the steps of:

a. on a first trip, lowering a perforating device equipped withperforating means through said tub- 12 ing string and locking saidperforating device within said tubing string;

b. on a second trip, lowering a remotely operable actuating device intoengagement with said perforating device, actuating said perforatingdevice to cause said perforating means to form one or more perforationsin said tubing string, releasing said perforating device from saidtubing string and thereafter recovering both said actuating device andsaid perforating device from said tubing string; and

. on a third trip, lowering a gas lift valve means into 2. A method asdefined in claim 1 wherein: a. said perforating device is anchored witha given collar recess formed between mating tubing sections; and

b. said gas lift valve means is anchored with said collar recess afterformation of said perforations and removal of said perforating device.

1. A method of providing gas lift valves in a conventional tubing stringcomprising the steps of: a. on a first trip, lowering a perforatingdevice equipped with perforating means through said tubing string andlocking said perforating device within said tubing string; b. on asecond trip, lowering a remotely operable actuating device intoengagement with said perforating device, actuating said perforatingdevice to cause said perforating means to form one or more perforationsin said tubing string, releasing said perforating device from saidtubing string and thereafter recovering both said actuating device andsaid perforating device from said tubing string; and c. on a third trip,lowering a gas lift valve means into said tubing string and anchoringsaid gas lift valve means into said tubing string and anchoring said gaslift valve means in said tubing in pressure communication with said oneor more perforations.
 2. A method as defined in claim 1 wherein: a. saidperforating device is anchored with a given collar recess formed betweenmating tubing sections; and b. said gas lift valve means is anchoredwith said collar recess after formation of said perforations and removalof said perforating device.